Count down timer - iPhone [closed]

Answer 1

this is the code for .h file:

@interface UIMyContoller : UIViewController {

NSTimer *timer;
IBOutlet UILabel *myCounterLabel;
}

@property (nonatomic, retain) UILabel *myCounterLabel;
-(void)updateCounter:(NSTimer *)theTimer;
-(void)countdownTimer;

@end

and here is the code for .m file:

@implementation UIMyController
@synthesize myCounterLabel;

int hours, minutes, seconds;
int secondsLeft;

- (void)viewDidLoad {
[super viewDidLoad];

secondsLeft = 16925;
[self countdownTimer];
}

- (void)updateCounter:(NSTimer *)theTimer {
if(secondsLeft > 0 ){
    secondsLeft -- ;
    hours = secondsLeft / 3600;
    minutes = (secondsLeft % 3600) / 60;
    seconds = (secondsLeft %3600) % 60;
    myCounterLabel.text = [NSString stringWithFormat:@"%02d:%02d:%02d", hours, minutes, seconds];
}
else{
    secondsLeft = 16925;
}
}

-(void)countdownTimer{

secondsLeft = hours = minutes = seconds = 0;
if([timer isValid])
{
    [timer release];
}
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];  
timer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(updateCounter:) userInfo:nil repeats:YES];
[pool release];
}

hope this helps. happy coding

adrian

Answer 2

I would recommend the below method of getting time components of From Date to To Date.

This method is more elegant than manually decrementing 3 integer variables for hour, minute and seconds because doing so would mean you have to manually check when a second hit 0, you need to manually reset the minute back to 59 and so on. I went down this route once, it wasn't very good.

Also, when you minimize your app, the count down clock will stop. If you were decrementing your count down timer manually using 3 integers (hour, minute and seconds), minimizing your app will cause the count down to screw up.

Since this method auto calculates the difference between two dates, even when the app returns from the background minimized state, it automatically recalculates the remaining time for you without any extra code.

-(void)viewDidLoad
{
    // instantiate a calendar object.
    gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

    countDownTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(updateClock:) userInfo:nil repeats:YES];
    [countDownTimer fire];
}

-(void)updateClock:(NSTimer *)timer
{
    countDownDateFormatter = [[NSDateFormatter alloc] init];
    [countDownDateFormatter setDateFormat:@"hh:mm:ss"];

    NSDate *now = [NSDate date];

    NSDateComponents *comp = [gregorianCalendar components:NSHourCalendarUnit|NSMinuteCalendarUnit|NSSecondCalendarUnit 
                                                  fromDate:now
                                                    toDate:countDownEndDate 
                                                   options:0];

    NSString *strTimeRemaining = nil;

    // if date have not expired
    if([now compare:countDownEndDate] == NSOrderedAscending)
    {
        strTimeRemaining = [[NSString alloc] initWithFormat:@"%02d:%02d:%02d", [comp hour],  [comp minute], [comp second]];
    }
    else 
    {
        // time has expired, set time to 00:00 and set boolean flag to no
        strTimeRemaining = [[NSString alloc] initWithString:@"00:00:00"];

        [countDownTimer invalidate];
        countDownTimer = nil;
    }

    lblCountDown.text = strTimeRemaining;

    [countDownDateFormatter release];
    [strTimeRemaining release];
}

Answer 3

you can set coundown like my below code :-

 -(void) viewWillAppear:(BOOL)animated
 {
 timer = [NSTimer scheduledTimerWithTimeInterval: 1.0 target:self selector:@selector(updateCountdown) userInfo:nil repeats: YES];
 }

AND

 -(void) updateCountdown 
 {

NSString *dateString = @"14-12-2012";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter setDateFormat:@"dd-MM-yyyy"];
NSDate *dateFromString = [[NSDate alloc] init];
// voila!
dateFromString = [dateFormatter dateFromString:dateString];


NSDate *now = [NSDate date];
NSCalendar *calendar = [NSCalendar currentCalendar];



NSDateComponents *componentsHours = [calendar components:NSHourCalendarUnit fromDate:now];
NSDateComponents *componentMint = [calendar components:NSMinuteCalendarUnit fromDate:now];    
NSDateComponents *componentSec = [calendar components:NSSecondCalendarUnit fromDate:now];        


NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *componentsDaysDiff = [gregorianCalendar components:NSDayCalendarUnit
                                                            fromDate:now
                                                              toDate:dateFromString
                                                             options:0];



lblDaysSetting.text=[NSString stringWithFormat:@"%02d",componentsDaysDiff.day];
lblHouresSetting.text=[NSString stringWithFormat:@"%02d",(24-componentsHours.hour)];    
lblMinitSetting.text=[NSString stringWithFormat:@"%02d",(60-componentMint.minute)];  
lblSecSetting.text=[NSString stringWithFormat:@"%02d",(60-componentSec.second)];  



 }

now just set your logic

its code output as my project as bellow::-